MPEJ Volume 13, No. 4, 24 pp. Received: May 4, 2006. Revised: Jan 16, 2007. Accepted: Jul 20, 2007. C.Fermanian Kammerer Normal forms for conical intersections in quantum chemistry ABSTRACT: In quantum chemistry, the dynamics of heavy molecules is described by Schr\"odinger equations with energy level crossings. These crossings generate energy transfers at leading order between the modes as was earlier noticed by Landau and Zener in the 30's. The mathematical analysis of these transfers relies on the use of normal forms. Here, we analyze the implications of Y. Colin de Verdi\`ere's recent result on normal forms in the context derived by G. Hagedorn for molecular propagation and extend these normal forms to codimension 5 crossings. http://www.maia.ub.es/mpej/Vol/13/4.ps http://www.maia.ub.es/mpej/Vol/13/4.pdf http://www.ma.utexas.edu/mpej/Vol/13/4.ps http://www.ma.utexas.edu/mpej/Vol/13/4.pdf http://mpej.unige.ch/mpej/Vol/13/4.ps http://mpej.unige.ch/mpej/Vol/13/4.pdf